Diesel cars - all bad?

reeac

Cornucopia wrote: »

A comparison between diesel and petrol engines in the same car is always going to help analyse the long-term differences between the two fuels.

A comparison with a fantasy Roller... not so much.

I think that you've missed the point. I chose the Roller in order to take the methodology to extreme to demonstrate that it isn't an actual saving if you've not bought the other car. It's like saying that by driving the 100 miles straight from A to B I've saved ££££ because I didn't take the scenic 200 mile route ...yes, you've chosen the cheaper option but you can't subtract that cost reduction (or mileage) from what you actually did incur., thus leaving a reduced actual amount. The cost that you did incur IS the actual amount.

kmb500

Ebe_Scrooge wrote: »

Well, diesel fuel contains more energy per litre than petrol does, so they are inherently more economical - that's a very broad rule of thumb, but generally true. I think the problem with diesels these days is the amount of "add-ons" that have had to be added to make them comply with ever-more stringent emission rules ( the DPF being one of the worst culprits ). Back in the olden days ( when I was learning to drive ! ), a diesel engine was pretty much the most simple engine in the world, with very little to go wrong.


I run a diesel car myself, but I do around 25,000 miles a year, the majority of which is high-speed motorway and open-road driving. Even with a very heavy right foot I get 52 mpg, much more than that if I take it a bit steadier. Touch wood, I've never had any problems at all with it - but then I guess I'm doing the sort of mileage that a diesel was intended for.

Much better than my car. I just filled up my tank and checked how many miles I'd done for the 40 litres I filled up. 200 miles... a whopping 22mpg. LOL.


My parents used to have a big Peugeot 406 diesel. We had gone to France on holiday for two weeks, and a couple of weeks after we got back, it ran out of fuel and had to be towed to a garage. My dad couldn't figure out why it had used so much fuel - then he realised that it hadn't been to a petrol station since leaving to go to France.

[Deleted User]

trailingspouse wrote: »

It's very simple. When I own a petrol car, every article you read will be about how economical diesel is and how the emissions aren't that bad really. The second I buy a diesel car, they change their minds.

This is basically what happened to me. Although I'm loving my diesel car, I'm getting moon mileage out of a tank of diesel compared to my last petrol car. I didn't pay a premium for it either, it's 8 years old not brand spanking new.

iolanthe07

kmb500 wrote: »

diesel engines are great, they are very economical. Seems to me that if you change a car from being petrol to diesel youll get 15-20% more mpg.

Yes - but there's so much more to it than that. Just read of all the problems people have with DPFs these days. Diesels are fine for long runs and high mileages, but if you use them for short stop/start shopping trips you are asking for trouble. Pre DPF diesles are OK, but may be legislated or taxed out of existence because they are so dirty.

System

iolanthe07 wrote: »

Yes - but there's so much more to it than that. Just read of all the problems people have with DPFs these days. Diesels are fine for long runs and high mileages, but if you use them for short stop/start shopping trips you are asking for trouble.

But that is people buying the wrong tool for the job, its not the fault of diesel cars.

easy

I currently have a diesel car (Volvo V40 D2), on a lease. It's the first diesel I've ever had in nearly 30 years of driving, and I and my hubby both love it. The lease will end this summer, and we were going to ask the leasing company for a price for my husband to buy it - it will be 3 years old, with about 34k miles - including having long motorway trips every few weeks to visit my mum who lives 130 miles away, so no DPF problems so far.
But hubby is now not so keen on buying it, simply because we don't know what is likely to be the fate of diesel cars, and whether the cost of diesel fuel will go astronomical.
My view is that it is a newer model (2014 reg) with a decent modern engine, and hence is unlikely to be "first against the wall when the revolution comes". So he should be able to run it for 3 or 4 years at least.
His main usage would be his 24 mile round trip commute in rush hour, but we would make sure it got it's fair share of motorway runs to clean the DPF from time to time.

I value the fact that the car has been in our hands from new, and we know it's history. But as its a diesel, would you buy it, or go and look for a petrol version whose history we don't know?

brownedge

Thanks for the very interesting replies to this thread on diesel vs petrol. My Fiesta diesel is still doing fine, on both long and short runs, consistently over 60 mpg if I can believe the computer (but no doubt you will dispute that). Anyway, the air here seems good to breathe. But I worry about the government's intentions regarding diesel.

Tyler119

brownedge wrote: »

Thanks for the very interesting replies to this thread on diesel vs petrol. My Fiesta diesel is still doing fine, on both long and short runs, consistently over 60 mpg if I can believe the computer (but no doubt you will dispute that). Anyway, the air here seems good to breathe. But I worry about the government's intentions regarding diesel.

I feel your worry, we have two diesel cars and financially it would be not realistic to get rid of them to replace with something of equally quality. I think going forward they will just end up being banded in the centre areas or cities and the larger towns. Personally I've no issue with this as I never drive in those areas and use public transport / leg power. I suppose another option would be to offer areas where people could drop off their car and drive in to the city using an electric car scheme. These cars could be quite small and thus would increase the amount of parking areas available on streets etc.

I don't envisage them being outlawed as the government would have to spend a great deal of public money creating financial incentives for people to scrap their diesel cars.

Any investment would likely be better spent on public transport infrastructure (the train network being one of them). A more efficient public transport network and one less costly would encourage further usage in cities...well that would be the positive idea anyway.

Another option would be for a remote kill code to be sent to all recent diesel cars...perhaps the government could partner up with VW on the secret implementation.

daveyjp

"fair share of motorway runs to clean the DPF from time to time"

You never fully clean a DPF - every time it regenerates ash is produced and this starts to block it. At some point the ash will be so dense a new DPF will be required.

As long as you are aware that it is a consumable item and have £1,000 to cover the potential cost then you can sleep easily.

giraffe69

When all the threats against diesel cars are made there is no attempt to distinguish between older diesels and new ones. for example will CAT6 cards be treated the same as earlier editions?
The press are into exaggeration. When diesel sales slipped 4.7% last month continuing a decline seen for some months this was a "crash" and a "collapse" in sales. Perhaps they have to use such words to get us to pay attention?